JP3370455B2 - Ground improvement equipment - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of mixing a solidifying material while stirring earth and sand in the ground to solidify the earth and sand.
The present invention relates to a ground improvement device suitable for improving soft ground. [0002] As is well known, a solidifying material such as lime or cement is prepared into a slurry, and the slurry is stirred and mixed with soil in the ground to form a hydration reaction of the solidified material slurry. The soil is chemically solidified by ion exchange between the hydration product of the hydration reaction and the clay mineral, or chemical consolidation mainly by the pozzolanic reaction, etc., and the improved pile is placed in the ground. There is a construction method of building and improving the ground. Conventionally, in such a ground improvement method, FIG.
Ground improvement device 1 based on pile driver as shown in
Is used. In the ground improvement apparatus 1, a stirring rod 4 is rotatably supported around an axis of a supporting column 3 provided on a main body 2, and a lower end portion of the stirring rod 4 stirs soil in the ground G. It has a schematic configuration including a wing 5, an earth auger 6 for agitating soil in the ground G, and a discharge port 7 for supplying a solidified material slurry into the ground G from a solidified material supply mechanism (not shown). ing. In order to improve the ground G using such a ground improvement apparatus 1, first, a stirring rod 4 is attached to the ground G.
, And penetrates the ground G with the earth auger 6 to a predetermined depth. Next, the solidified material slurry is supplied to the discharge port 7 at the lower end of the stirring rod 4 by the solidified material supply mechanism.
Squirt from Then, while pulling up the stirring rod 4, the ejected solidified material slurry and the soil of the ground G are stirred by the earth auger 6 and the stirring blades 5, thereby solidifying the soil and forming a columnar improved pile in the ground G. Create. [0005] In accordance with a structure to be constructed on the ground G or the purpose of use of the ground G, such an improved pile is used.
The ground G has been improved singly or in blocks, grids, continuous walls, or the like. [0006] However, the conventional ground improvement apparatus as described above has the following problems. That is, since the earth auger 6 that moves in the ground G is provided only at the lower end of the stirring rod 4, the improved pile formed in the ground G has an outer shape of:
It had to be cylindrical with a diameter equal to the rotation diameter of the earth auger 6. Therefore, when it is desired to improve the ground G over a wide area, a large number of improved piles are formed, or improved piles are formed at appropriate intervals, and only the surface layer between the pile heads of these improved piles is separately ground- improved. Therefore, there is a problem that the construction period is prolonged and the construction cost is increased. The present invention has been made in consideration of the above points, and has as its object to provide a ground improvement device that can efficiently improve the ground at low cost. SUMMARY OF THE INVENTION The present invention relates to a ground improvement apparatus for improving a ground by mixing a solidified material with earth and sand in the ground, the apparatus being rotatable about an axis and extending in the axial direction. A stirring rod movably provided in the ground, a solidifying material supply mechanism for supplying a solidifying material into the ground is provided, a lower end portion of the stirring rod, a first stirring blade fixed to the stirring rod,
The second stirring blade consisting of one or more wings is vertically separated by a certain distance.
The wing body of the second stirring blade is provided at an interval, and a base end portion thereof is rotatably supported on the stirring rod in a horizontal plane within a certain angle range. The radius of rotation of the second stirring blade in a state in which the tip of each blade body is separated from the stirring rod can be separated from and approachable to the stirring rod, and is larger than the rotation radius of the first stirring blade. The first stirring blade and the second
A discharge port for solidified material is provided at the base of each of the two stirring blades.
And the solidified material in one of these outlets
Switching valve for selectively supplying
It is characterized in that there. The ground improvement apparatus according to the present invention includes a stirring rod having first stirring blades and second stirring blades, a solidifying material supply mechanism, and each blade of the second stirring blades is fixed at a predetermined angle. It is configured to be rotatable in the range of. As a result, the stirring rod penetrates into the ground while rotating, and the first stirring blade and the second stirring blade
Either one of the discharge ports provided at the base of the stirring blade
Then, the solidified material is jetted into the ground and mixed with the earth and sand in the ground with stirring blades, whereby the ground can be solidified and improved. At this time, since the base end of the blade body of the second stirring blade is supported by the stirring rod, when the stirring rod is rotated in one direction, the tip end of each blade comes into contact with the surrounding ground. The wing body rotates in a direction in which the tip end is separated from the stirring rod by the reaction force caused by the pressure, that is, the earth pressure.
In this manner, the radius of rotation of the second stirring blade becomes larger by a certain dimension than that of the first stirring blade. On the other hand, when the stirring rod is rotated in the opposite direction, the earth pressure from the surrounding ground causes
The blade rotates in a direction in which the tip approaches the stirring rod, whereby the radius of rotation of the second stirring blade is reduced. The present invention will be described below with reference to an embodiment shown in the drawings. Here, the ground improvement device according to the present invention,
For example, a description will be given using an embodiment in a case where the present invention is applied to a biaxial ground improvement apparatus having two drilling rods. As shown in FIG. 1, the ground improvement device 10 includes an endless caterpillar 1 for movement.
A support column 12 is vertically provided in front of a main body 11 having 1a,
A hole for drilling and agitating the ground G on the support column 12
The agitation mechanism 13 is provided, and further, a solidification material supply mechanism (not shown) for supplying the solidification material to the ground G is provided. [0010] As shown in FIG.
Is provided with two stirring rods 15 and 15. As shown in FIG. 1, the stirring rods 15, 15
Each upper end is connected to the drive motor 16. When the drive motor 16 is driven, the stirring rods 15 and 15 are driven to rotate around their respective axes in opposite directions. In addition, the stirring rods 15, 15 are rotatably supported around their axes at the intermediate portion thereof by a guide member 18 provided to be able to move up and down along the columns 12. A drive motor 16 is provided so as to be vertically movable along the support column 12, and thereby the stirring rod 1 is provided.
5 and 15 are configured to be vertically movable integrally with the drive motor 16. Behind the main body 11, a pulling winch 20 is provided.
The pulling winch 20 has one end of a wire 21 fixed thereto. And wire 21
The other end of the support member 2 is provided at the upper end of the support column 12.
2 and a sheave 25 rotatably supported on the upper surface of the drive motor 16.
Is fixed to the lower surface of the support member 22 via the support. As a result, when the wire 21 is wound up by the pulling winch 20, the drive motor 16, that is, the stirring rods 15, 15 rises along the support columns 12. Also,
When the wire 21 is drawn out from the drawing winch 20, the stirring rods 15, 15 are moved by the own weight of the drilling / stirring mechanism 13.
Descend along the support pillars 12. As shown in FIG. 2, each of the stirring rods 1
At the lower end of 5, a first stirrer blade 27 and a second stirrer blade 28 are provided so as to be vertically spaced apart from each other by a certain dimension and to be orthogonal to each other in plan view. And the stirring rods 15 and 1
An interference band 29 is provided at the lower end of 5 so as to keep the distance therebetween. The first stirring blade 27 is formed integrally with the stirring rod 15, and at the tip thereof, bits 30, 30,... For efficiently stirring the ground G are provided. On the other hand, the second stirring blade 28 is provided with blades 31, 31 having a substantially J-shape in plan view. Each wing 3
Reference numeral 1 denotes a form that is sandwiched between an upper member 32a and a lower member 32b of a pedestal 32 formed integrally with the stirring rod 15. As shown in FIGS. 3 and 4, the pedestal 32 is provided with a pin 33 extending parallel to the axial direction of the stirring rod 15. The base end 31a of each wing 31 is rotatably supported by the pin 33, so that each wing 31 is rotatable in a horizontal plane. Each pedestal 32 is integrally formed with a stopper 34 for regulating the rotation angle of the wing body 31. As shown in FIG. 3, when the tip 31 b of the blade 31 rotates in a direction away from the stirring rod 15, the stopper 31 causes the blade 31 to hit the stopper 34. Further, as shown in FIG. 4, when the wing body 31 rotates in a direction in which the tip part 31b approaches the stirring rod 15, the tip part 3 of the wing body 31 is rotated.
1 b corresponds to a stopper 34 provided on a pedestal 32 of the other wing body 31. In this manner, the wing bodies 31, 31 constituting the second stirring blade 28 are provided with the pins 33,
It is configured to be rotatable around a predetermined angle within a horizontal plane around the center 33. Then, as shown in FIG. 3, when the stirring rods 15, 15 are driven to rotate in the direction of the arrow in the figure, the reaction force generated between the stirring rods and the surrounding ground, that is, the earth pressure, causes the tip portions 31b, 31b. Of the second stirring blade 28 rotate in a direction in which the base member 3 separates from the stirring rod 15, and the base end 3
1a and 31a are in a state of hitting the stoppers 34 and 34 (hereinafter, this state is referred to as an "expanded state"). As shown in FIG. 2, when this state occurs, the wing 3
The rotation radii of the first and second stirring blades 28, that is, the rotation radii of the second stirring blade 28 are larger than the rotation radius of the first stirring blade 27 by a certain dimension. Further, as shown in FIG. 4, when the stirring rods 15, 15 are rotationally driven in the direction of the arrow in the figure, the tip portions 31b, 31 are caused by the earth pressure from the surrounding ground.
The blades 31, 31 of each second stirring blade 28 rotate in the direction in which the b approaches the stirring rod 15, respectively, and the tip portions 31b, 3
1b is brought into contact with the stoppers 34, 34 (hereinafter, this state is referred to as "diameter reduction state"). In this state, the rotation radius of the second stirring blade 28 is the same as the rotation radius of the first stirring blade 27 (see FIG. 2). As shown in FIG. 2, discharge ports 36 and 3 are provided at the bases of the first stirring blade 27 and the second stirring blade 28 as described above.
7 are provided. One end of a slurry hose (not shown) passing through the stirring rod 15 is connected to the discharge port 36 of the first stirring blade 27. The discharge port 37 of the second stirring blade 28 is provided inside the interference band 29 and the stirring rod 15.
One end of a slurry hose (not shown) passing through the inside is connected. The other end of the slurry hose is connected to a slurry pumping pipe 38 disposed between the stirring rods 15. On the other hand, on the ground, a slurry manufacturing apparatus (not shown) for kneading the solidified material slurry with a predetermined composition is installed. The slurry producing apparatus is provided with a solidification material supply pump for feeding the solidification material slurry toward the discharge ports 36 and 37. The solidified material supply pump includes the slurry hose connected to the discharge port 36,
The slurry pressure feed pipe 38 connected to the discharge port 37 is connected. Further, the slurry manufacturing apparatus is provided with a switching valve for switching which of the discharge port 36 and the discharge port 37 feeds the solidified material slurry.
In this manner, the solidified material slurry kneaded in the slurry manufacturing apparatus is switched by switching the switching valve.
The gas is ejected from the discharge port 36 or 37 into the ground G. Next, a ground improvement method using the ground improvement apparatus 10 having the above configuration will be described in detail. First, ground G
The stirring rods 15 and 15 are positioned at predetermined positions. Next, the drive motor 16 drives the stirring rods 15, 15 to rotate, thereby rotating the first stirring blades 27, 27 and the second stirring blades 28, 28 in the directions indicated by arrows in FIG. Then, the pulling winch 20 is operated to draw out the wire 21. Then, the first stirring blades 27, 27 rotate and penetrate into the ground G by the own weight of the drilling and stirring mechanism 13. At this time, as shown in FIG. 4, the wing bodies 31, 31 of the respective second stirring blades 28 are in a reduced diameter state due to the earth pressure (reaction force) from the surrounding ground G. At the same time, the solidified material slurry is ejected from the discharge ports 36, 36 of the first stirring blades 27, 27 into the ground G. Then, the ejected solidified material slurry is supplied to the first stirring blades 27 in the ground G by the first stirring blades 27, 27.
Is mixed with earth and sand within the radius of rotation. Thereafter, when the first stirring blades 27, 27 reach a predetermined depth, the feeding of the wire 21 by the drawing winch 20 is stopped, and the stirring rods 15, 1 are stopped.
Stop descent of 5. And the stirring rods 15, 15
While the is rotated, the solidified material slurry is continuously ejected from the discharge ports 36, 36 into the ground G for a certain period of time to perform the tip treatment of the improved pile. Next, while the stirring rods 15, 15 are being rotated in the above-described rotation direction, the wire 21 is wound up by the drawing winch 20, and the stirring rods 15, 15 are pulled up. When the second stirring blades 28 rise to a predetermined depth, the rotation direction of the drive motor 16 is switched, and the stirring rods 15, 15 are reversed. Then, as shown in FIG. 3, the blade body 3 of each second stirring blade 28
Due to the earth pressure from the surrounding ground G, the tip portions 31b, 31b rotate in a direction away from the stirring rods 15, 15 to be in an expanded state. At the same time, the switching valve (not shown) of the slurry manufacturing apparatus is switched to eject the solidified material slurry from the discharge ports 37 of the second stirring blades 28. And stirring rod 1
Continue raising 5,15. Then, the discharge port 37,
The solidified material slurry ejected from 37 is supplied to the second stirring blade 2
Due to 8, 28, the mixture is agitated and mixed into the ground G within the range of the radius of rotation of each second stirring blade 28. As described above, the first stirring blades 27, 27
The solidified material slurry discharged from the discharge ports 36, 36 and the discharge ports 37, 37 of the second stirring blades 28, 28 are respectively separated by the first stirring blades 27, 27 and the second stirring blades 28, 28. It is stirred and mixed with the earth and sand of the ground G. The soil is formed by a hydration reaction of the solidified material slurry mixed with the earth and sand, an ion exchange action between the hydration product of the hydration reaction and the clay mineral, or a chemical consolidation reaction mainly including a pozzolan reaction. As a result, the improved pile A is formed in the ground G as shown in FIG. In the improved pile A thus formed, the deep portion has a small diameter portion A1 having the same diameter as the rotation radius of the first stirring blade 27, and the surface portion has the same diameter as the rotation radius of the second stirring blade 28. Has a large diameter portion A2. Thereafter, the above steps are repeated to form a predetermined number of improved piles A at predetermined positions,
The improvement of the ground G is completed. At this time, if a plurality of improved piles A having such a shape are formed so that the surface portions A2 are adjacent to each other, the ground G can be improved over a wide range. In the above-described ground improvement apparatus 10, the stirring rods 15, 15 having the first stirring blades 27, 27 and the second stirring blades 28, 28, and the solidification material supply mechanism are provided. The wing bodies 31, 31 constituting the wing 28 are rotatable in a horizontal plane within a certain angle range. As a result, the stirring rods 15, 15 are made to penetrate the ground G while rotating, and the solidified material slurry supplied into the ground G by the solidified material supply mechanism is supplied to the first stirring blades 27, 27 and the second stirring blades 28, 27. By mixing and mixing with the earth and sand in the ground G at 28, the improved pile A having a small diameter in the deep part and a large diameter in the surface part can be formed in a single step. And, even when the ground improvement that is wide only in the surface layer is required, the ground G can be improved with a smaller number of improved piles A than before by forming a plurality of improved piles A having such a shape. . As a result, the ground G can be efficiently improved at low cost and in a short period of time. In addition, the wing body 3 constituting the second stirring blade 28
1, 31 are rotatably supported by the pins 33, 33,
It is configured to be rotatable within a certain angle range. As a result, when the stirring rods 15, 15 are driven to rotate in one direction, the wing bodies 31, 31 are automatically expanded by the earth pressure from the surrounding ground G, and the stirring rods 15, 1 are also expanded.
If 5 is reversed, the diameter is automatically reduced by the earth pressure from the surrounding ground G. Therefore, the stirring rods 15, 1
By simply switching the rotation direction of No. 5, the rotation radius of the second stirring blade 28, that is, the pile diameter of the improved pile A can be easily changed. In addition, since no drive source is required to expand and reduce the diameter of the second stirring blade 28, it is possible to manufacture the ground improvement device 10 that can exhibit the above-described effects at low cost, and The occurrence of a failure or the like can be suppressed. As a result, the cost for improving the ground G can be reduced. The solidified material slurry discharged from the discharge port 36 of the first stirring blade 27 and the discharge port 37 of the second stirring blade 28
By changing the composition with the solidified material slurry discharged from the above, the pile strength of the small diameter portion A1 and the large diameter portion A2 of the improved pile A can be easily changed. Therefore, even when the improvement strength of the ground G is changed depending on the place, this can be easily performed. In the above embodiment, the diameter of the second stirring blade 28 is expanded only in the surface layer of the ground G. However, if necessary, the diameter of the second stirring blade 28 may be expanded. Good. For example, as shown in FIG. 6, in the range indicated by reference numeral (a) in the figure, the drive motor 16 is rotated forward to set the second stirring blade 28 in a reduced diameter state, and is indicated by reference numeral (b) in the figure. Within the range, the drive motor 16 may be rotated in the reverse direction to make the second stirring blade 28 in the expanded state to form the improved pile A ′. In the improved pile A 'thus formed, the small-diameter portion A1' formed by the first stirring blade 27 and the large-diameter portion A2 'formed by the second stirring blade 28 are alternately continuous in the vertical direction. And has a multilayer structure.
If a plurality of such improved piles A 'are formed so that the large-diameter portions A2' are adjacent to each other, it is possible to improve the ground G into a rigid frame structure. In the above embodiment, the number of the stirring rods 15 provided in the ground improvement apparatus 10 is not limited, and it is needless to say that one or three or more stirring rods may be provided. Further, the shape and number of the wing bodies 31 provided in the second stirring blade 28 are not limited. In addition, to prevent lateral displacement of the ground G,
A spiral wing may be formed on the stirring rod 15 so that the earth and sand in the ground G stirred by this may be discharged to the ground. As described above, according to the ground improvement apparatus of the present invention, the first stirring blade and the second stirring blade are vertically moved.
A stirring rod provided so as to be separated by a fixed size , a solidifying material supply mechanism, and each blade body of the second stirring blade is configured to be rotatable within a certain angle range, the first stirring blade and the second stirring blade Disturbance
In addition to providing a solidified material discharge port at the base of the stirring blade
And the solidified material is selectively supplied to one of the discharge ports.
A configuration was provided with a switching valve for supplying. Thereby, the solidified material supplied into the ground from any one of the discharge ports is made to penetrate the ground while rotating the stirring rod ,
The improved pile having a large-diameter portion and a small-diameter portion can be formed in a single step by stirring and mixing with the earth and sand in the ground with either the first stirring blade or the second stirring blade . Therefore, the ground can be improved with a smaller number of improved piles than before, and as a result, the ground can be efficiently improved at low cost and in a short period of time. In addition, the wing body constituting the second stirring blade is configured to be rotatable within a certain angle range. This allows the rotation radius of the second stirring blade, that is, the pile diameter of the improved pile, to be automatically changed only by switching the rotation direction of the stirring rod in accordance with the earth pressure from the surrounding ground. An improved pile having a small diameter portion at an arbitrary position can be easily formed. In addition, since no drive source is required to expand and contract the wing body, it is possible to manufacture a ground improvement device capable of achieving the above effects at low cost, Etc. can be suppressed. As a result,
This can also reduce the cost required for ground improvement.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side view showing an example of a ground improvement device according to the present invention. FIG. 2 is a front view showing a first stirring blade and a second stirring blade provided in the ground improvement device. FIG. 3 is a cross-sectional plan view showing a state where the diameter of the second stirring blade is expanded. FIG. 4 is a plan sectional view showing the reduced diameter state. FIG. 5 is a vertical sectional view showing an example of the ground improved by using the ground improvement device. FIG. 6 is a vertical sectional view showing another example of the ground improved by using the ground improvement device. FIG. 7 is a side view showing an example of a conventional ground improvement device. [Description of Signs] 10 Ground improvement device 15 Stirring rod 27 First stirring blade 28 Second stirring blade G Ground

──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Junji Tanaka 1-13-23 Kashidaidai, Higashi-ku, Fukuoka City, Fukuoka Prefecture (72) Inventor Sumio Ito 4-76, Matsugaoka, Kasuga City, Fukuoka Prefecture (56) References JP 59-10610 (JP, A) JP-A-60-98009 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E02D 3/12 102

Claims (1)

(57) [Claim 1] A ground improvement device for improving a ground by mixing a solidified material with earth and sand in the ground, wherein the device is rotatable about an axis and moves in the axial direction. A stirring rod that is freely movable, and a solidifying material supply mechanism that supplies a solidifying material into the ground. A lower end portion of the stirring rod includes a first stirring blade fixed to the stirring rod, and one or more stirring blades. A second stirring blade made of a wing body is vertically spaced apart by a certain dimension , and each wing body of the second stirring blade has its base end pivotally supported by the stirring rod and has a fixed angle range. The second stirring blade is rotatable in a horizontal plane, the tip of which is separated and approachable to the stirring rod, and the tip of each wing body is separated from the stirring rod. The rotation radius of the first stirring blade is larger than the rotation radius of the first stirring blade by a certain dimension. ,
The blades of the first stirring blade and the second stirring blade are respectively
The outlet for the solidified material is provided and the solidified material is
To selectively supply one of these outlets
A ground improvement device comprising a switching valve .